FIXED: Idle was HIGH, now too low, popping and missing VIDEO, Solution was CHT Options

[ctc911ctc]

I could not get the idle down below 1800, I took the advice from the excellent suggestions within 914world-garage and replaced EVERY gasket in the vacuum chain, including fixed a leaky plenum. """But mine looked so good - it can't be leaky! """ It was VERY leaky!

When I rebuilt the plenum (both sides of the support columns were leaky) and put it all back together, the resulting idle was way too low. I now have the reverse problem!

If I open up the ARR (remove hose) the idle is still low. If I take off the air cleaner and loosen the idle screw (all the way) still around 800-900. hhhhmmmmm.....

Throttle works, car will rev.
When driving the car it runs ok, however it does not have the power it used to have.

Engine is popping/missing, though the audio is not optimum, check out the video:

https://youtu.be/p5uM67DXJnk

Looking for next steps, what would you do next?????? (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/WTF.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

Background; '74 2.0 all STOCK with 20K miles, I have rebuilt:

throttle sensor PCB
Throttle control - does not leak, very smooth control, set spec on the electrics.
MPS - tested and perfect
PCV - seems to work
Injectors - just back from Hurst injectors - all on spec
Distributor - clean and spiffy, advance works
plugs - new
AAR - tested and works
Computer Control Unit - I have 2, have swapped them and they both perform the same.
Flow Down - on spec
Dwell set
Timing set

Many thanks in advance

CTC911CTC

[r_towle]

is the CHT plugged in?
you are still getting air in.
2.0 liter runs rich OOTB.

Here is how I figure it out.
Remove everything from the plenum except the hose to the MPS.
Tape over all the other holes, including and especially the AAR valve.
Now start it...
Assuming your timing is correct, you should have full control over the idle with that bleed screw now.
If not, its the MPS at fault...its the only thing you left connected to the plenum, right?

if you are good, then its just a process of elimination to find the fault as you add back on hose or system at a time.

rich